@lanechanger: It gets better! Aura mods give you more mod power to use, so it's a good idea to use an aura with the correct polarity (as this doubles it's power contribution) for your warframe.
And with Forma you can later add even more mod power by changing (or adding) polarity to one slot - with the drawback that the warframe/weapon/sentinel is reset to rank 0 (but keeps reactor/catalyst if applied) - effectively, it's a "prestige mechanic".
@deranged: It's also available on PC! ;)
You can find the system requirements here.